1. Technical Field
The present invention relates generally to a heterogeneous network in which a plurality of small cells is present in a large cell and, more particularly, to an apparatus and method for performing inter-cell interference coordination using limited channel state information in a heterogeneous network, which are capable of performing interference coordination using statistical information about a channel between each base station and each terminal in order to improve the throughput of a heterogeneous network in which a large cell and one or more small cells are present together in a mobile communication environment.
2. Description of the Related Art
A heterogeneous network model in which one or more small cells, such as a picocell, are located in a macrocell, that is, an existing large-sized base station, is attracting attention as a method of increasing throughput in a mobile communication environment. A heterogeneous network model is being considered for key technology for the next generation mobile communication standard, such as LTE-Advanced.
In a heterogeneous network, a Range Expansion (RE) technique for increasing coverage while maintaining the transmission power of a small cell base station without change is used to reduce the load of a large cell and to increase the utilization of a small cell. In this case, in a small cell terminal located in extended coverage, the intensity of interference transmitted from a large cell base station is higher than the intensity of a signal transmitted from the small cell base station, and thus serious deterioration of performance occurs.
Accordingly, in order to overcome the above problem, Inter-Cell Interference Coordination (ICIC) techniques have been proposed. These techniques mainly prevent a large cell base station from transmitting signals during a predetermined period of time, or utilize a transmission power control technique. The inter-cell interference coordination techniques that are disclosed in Korean Patent Application Publication No. 2012-0123718, etc. assume that information about channels between all terminals and a base station is completely known, or do not utilize channel state information. The former case is problematic in that the assumption about the channel state information is not consistent with an actual situation, and the latter case is problematic in that it is impossible to perform adaptive resource assignment based on channel states.
Accordingly, in light of the disadvantages of the conventional technologies, there is a need for new technology that performs interference coordination based on limited information about the states of channels between a large cell base station and small cell terminals. For this purpose, the probabilistic modeling of channels between a large cell base station and small cell terminals and a new interference coordination apparatus and method using a corresponding model need to be proposed.